ISC, ISCe, QSC8.3, ISL, ISLe3, ISLe4 and QSL9 Engines – Lubricating Oil Sludge in the Crankcase Excessive

Symptom Tree  t106

This is symptom tree t106
Cause Correction

Bulk oil supply is contaminated

Check the bulk oil supply. Drain the oil and replace with noncontaminated oil. Replace the oil filters. Refer to Procedures 007-013 and 007-083.


Lubricating oil does not meet specifications for operating conditions

Change the oil and filters. Refer to Procedure 007-013 and 007-037. Use the oil type recommended in Section V of the engine operation and maintenance manual.


Lubricating oil drain interval is excessive

Verify the correct lubricating oil drain interval. Refer to the Operation and Maintenance Manual, ISC and ISL Series Engines, Bulletin 4021428 or Operation and Maintenance Manual, QSC8.3 and QSL9 Engines, Bulletin 4021518.


Crankcase ventilation system is plugged

Check and clean the crankcase breather and vent tube. Refer to Procedure 003-008.


Fuel grade is not correct for the application or the fuel quality is poor

Operate the engine from a tank of high-quality fuel. Refer to the Fuel for Cummins Engines, Bulletin 3379001.


Coolant temperature is below specification

Refer to the Coolant Temperature is Below Normal symptom tree.


Lubricating oil is contaminated with coolant or fuel

Refer to Lubricating Oil Contaminated symptom tree.


Crankcase pressure is excessive

Check for excessive blowby. Refer to Procedure 014-010.


Exhaust system restriction is not within specification

Check the exhaust system for restrictions. Refer to Procedure 011-009.


Coolant temperature is above specification

Refer to the Coolant Temperature Above Normal – Gradual Overheat or Coolant Temperature Above Normal – Sudden Overheat symptom trees.

Last Modified:  20-Jun-2005